Dude, who even knows.
From paying close attention to my stride, I’m thinking the thing is the old flatfooted walking transmitted force up my legs to the sacrum, and from there up the spine to the skull?
Whereas the arched-foot style still transmits force to the hip bone, but it’s almost like force there is transmitted through muscles in the lower back and stretching from the broad lever-ends of the ilia, and the lumbar vertebrae are held fixed by that for force to be transmitted upwards?